Shock absorber



May 8, 1956 H. 1 F. ENLUND SHOCK ABSORBER Filed May 1, 1952 INVENTOR HEL MER L F WL UND luf ATTORNEY United States ,ljltdi 2,744,747 sHocK ABsoRBER Heimer r.. F.- Enlund, oak Ridge, Tenn. Application May 1, 1952, seriai'No. z ss,s 2s

` s claims. (cl. 267''1)Y 2,744,747 Patented Ma'y 8, 1956 andgh-old the abutment'head 88 in the path of travel-of the weight 27. 1

,The abutment, head 88Y comprising a downwardly directedfsocket 90, Fig. 3, that contains the end piece 91 whichis attached to'the plunger rod 84 at its end. -A

, buffer-,block 92, of wood or other suitable shockabf sorbing material, is` also contained in the socket 90 interposed betweentheabutment head 88 land the end piece 91.A The'rabutmenthead 88 in` addition comprises-the;

. (Grantedunder Tine 3s, U. s. code (1952), sec. 266i The invention .described herein may be manufactured.

and used by or for the Governmentof the.y United States. of America for governmental purposes withoutfthe. pay-, ment of any royalties thereon or therefor. t k.This invention concerns a shock absorber suitable for use inv arresting ay body of large mass moving athigh velocity.

` The shock absorber is found particularlyusefulwithguillotine-type impact testers having a tower ir1 wl iicl 1` a mass falls from an elevated position to the bottom of the., tower. It is necessary to arrest the mass without damaging.

parts Lof lthe. tester. The shock absorber embodies l a.I tapered pin that during the arresting action can .move

progressively into; anori'ce to restrict` progressively the flow of hydraulic lluid through the orifice. k,

An object of `the' invention is toV provideffashocl'cf'v absorber.

Another object is to provide a shock absorber st iital'ile` forzuse with an impact tester.

Other objects and many of the fgIn Figs. 1-3 is shown an impacttester cement base 70 sets on a floor 48, which is p r'ovi fcllt; c l.witlifv a cavity 79 disposed in line with the path of travel of the weight 27 through apertures.71. and 7 4 respectively of anvil 21 and base 70. The 'cavity 79 vcontains the shock absorber y80-.that'operatesfto brake-the fall of the weight Y27 and the ruptured piece Vofthe specimen .-26

that `is attached'to it. The shock absorber 80. is supportedby thebrackets 81'which areseated rigidlyv mthe c avity 79 as shownin Figs. 1 A and 2thev shock-ab orber being heldby the brackets in'alignment lwith the falling weight'27 and in position to receive and absorb the impact thereof. f

-The shock absorber 80 is of the hydraulic y.type and comprises a cylinder 8 2 that is di sposedin line,.wit l 1t he p ath of travel of the speci men assen 1l 3lyf r 25 asqletined' by the.' gyidewys. '55- -..A .Pisten @plunger strides-rin the cylinder 82. Plunger rod 84 is attached to plunger 83 and projects upwardly therefrom through the end of head 85 of the cylinder 82 to a position between the guideways 55 somewhat upwardly of their lower ends. See Figs. l, 2 and 3.

An abutment head 88 is attached to the end of the plunger rod 84 at its upper end, and comprises the laterally projecting lugs 89 that form oppositely directed slots which engage the respective opposite guideways 55 attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the vfollqvving] connection, with vtaken parts j upwardlyadirec'tedsocket -93 which. contains the similar buiferwblock 94 in position to be struckby lthe falling weight'27. i .Theplunger is backed in the cylinder.82 by the compression spring 95, which is `enclosed lwithin the; cylinder-.wall andextendsfrorn the plunger 83 at its one end-,to ythe cylinder5end' 96 at its otherin seating engage, mentfvwitlreach The spring 95 operates to urgejthe; plunger 83 upwardly to. project its abutment head 88 toits extendedv position illustrated in Fig. 2. v

^ A huid reservoir 100 isattached tothe top of the cy1inf der 82 exteriorly thereof. j A riser extendsv from the cy1in;

-der 82 below. the plungerY S31-to the reservoir. 100. 'Ifhe;

riser c onilstrises,the` standpipeA 101 thatentersthe reserf voir. frem;.below, the tube or.pipe 102 that projects' upwardly into,`the,cylinder.82 for a predetermined dis.

-..; tance-through tslower end or head 96, and a 180 elbow;

connecting the pipe 102with the standpipey 101,attl1jeir lower ends. Fluid is ableto flow from the. reservoir,100 into thecylinder cavity below the-plunger8'3 through the risers 101, 102-103j when the plunger 83 moves.

upwardly in cylinder82. The passage 104 in the cylinA-.i

der wall enables tluid to be scavenged out of the cavity` inthe cylinder 82 above the plunger 83 into `the. peservoir 100, and the longitudinal slot 105 in the cylinder wall intersects with the passage 104 to prevent tluid from being-trapped in the.'y cylinder 82 abovethe passage 104` when the plunger`83 approaches the topV of. its stroke.-

The reservoir 100 is provided with a lling plug 106,4. and a .'drainjplug 107, vthe latterserving toldeterrnine the*V levelfgf.;ltlidfsupplysinthe reservoir- The "pipe 102 projects upwardly into the cylinder-82 to a predetermined height. The tapered needle I108 is.l attached Ito the plunger 83 toproject downwardly-there. from=into the end ofthe pipe 102, and nthisrposition the,.need1e 108 constricts the passage that extends from the cavity of cylinder 82 below the plunger 83 through` pipe 102, elbow 103 and riser 101 to reservoir 100.' When; the plunger 83,is in its uppermost position, the passage inte the vpipe 1,02 is open toits. fullest extent. plunger 83 moves downwardly inthe.I cylinder 82, the, cross-sectional `area of the needle 108 becomes progressively greater proximate to the end ofthe pipe 102andI f the-needle 108 thereby operates as a valve that restricts thepassage intotl 1e pipe 102 in progressively increasingy increments.;

. When `aspecimeri ,'26 becomes ruptured, the Weight 27j with the attached portion of i the ruptured specimen 26f` c ontinues tojfalll until'it strikes thebuler bloclv 9,4 of the abutmenthead 88, l.The impact* drives the plunger'4 83 downwardly, in.ylinderl 8 2 against actiony of the springs95; to thereby absorb shock of impact ofthe weight-27.

Downwarggtravelof plunger` 83 operates .tol aetupate flaitlrtqllghi diamine .1.02f.1fr..0In which theuid tinus;

As the,

This provides a hydraulicA 3 second medium-for absorbingshock of the falling weight 27.

The progressively increasing effective area of the needle 108 proximate to the upper end of pipe 102 incident to downwardtravel ofthe plunger 83 operates to 4decrease the area of the uid passage into the pipe 102 progressively, and thereby serves to regulate the resistance 4to fluid flow with the downward travel of the plunger 83. Travel of the weight 27 is thereby retarded hydraulically in -lmagnitudes that may be'substantially constant, or that -ma-y increase progressively with the downward travel of the abutment head 88. The -valve of needle 108 operates to Lregulate resistance to travel of the plunger 83 in incre ments that may be substantially constant, or 'that `increase progressivelyfas the velocity 'of the weight 27 is decreased, and therefore as the shock of impact of the weight 27 against the buffer block 94 becomes absorbed and reduced and accordingly less violent. The distance that the weight 27 is required to/travel after rupture of specimen 26 and until it is brought to a stop is greatly reduced by the hereinbeforefdescribed shock absorber of the present invention,

When the weight 27 Vstrikes the buffer block 94, "and the `'plunger 83 is thereby driven downwardly, downward travel of the plunger 83 is arrested-and it is brought to' a stopfby the combined actionof `the several retarding mediums hereinbefore described Vbefore the needle 108 has travelled far enough to close the passage into the pipe 102 completely, After the weight 27 travels to its extreme position in a downward direction, it is raised-slowly-by action of the spring95 until the weight 2,7 and the springy 954 are brought into counterbalance.

Obviously many modifications and variations of the present invention are possible in the light of the vabove teachings. It is therefore to be understood that within the scope of the appended claims the invention may be' cylinder; a compression coil spring in said cylinder andv bearing against said piston and said lower cylinderfhead;

a fiuidreservoir formed with a bore at its lower end'and positioned adjacent the upper-end of said cylinder and in fluid communication with the upper end of said cylinder; pipe'means for permitting fluid communication between said uid reservoir and the lower portion of said cylinder, said pipe means at'one end thereof extending through the bore ofV said lower cylinder head into the lowerend of said cylinder and sealed to said lower cylinder head-and at its-other end sealed into the bore formed in the lower end of said uid reservoir, the end of said pipe means which extends into the lower end o f said cylinder registering with the conical extension of said piston whereby 4it is progressively constricted upon movement of said conical extension into said pipe means; and a quantity of shock absorbinguid normally occupying a portion of vsaid iiuid reservoir and all space in said shock absorber 'below said fluid reservoir.

`2. A ,shock absorber comprising an upright cylinder; an upper anda lower cylinder head, each head formed t i with an axial bore and secured in the upper and lower ends of said cylinder, respectively; a piston reciproeable in said cylinder; a plunger rod secured to said piston and extending through the bore formed in said upper cylinder head; an elongated conical extension secured to and extending from said piston toward the lower end of said cylinder; a compression coil spring in said cylinder and bearing against said piston and said lower cylinder head; means forming with the wall of the upper end of said cylinder an annular uid reservoir coaxial with said cylinder and in fluid communication with the upper end of said cylinder through a small b ore formed in the wall of said vcylinder adjacent the bottom of said Huid reservoir; large diameter pipe means for permitting uid communication between said fluid reservoir and the lower portion of said cylinder, one end of `said pipe means sealed in the bore of said lower cylinder head and extending part way into the lower end of said cylinder and adapted for registration with said conical extension, the other end of said pipe means sealed in a b ore formed in the bottom of said vfluid reservoir; whereby the opening in 'the end of said pipe means'which extends into the lower end of said cylinder is progressively constricted upon movement of saidconical extension into said pipe means; and a quantity of shock absorbing "fluid for occupying a portion of said fluid reservoir and all space in said shock absorber below said fluid reservoir. p

3. A shock absorber comprising an upright cylinder; an upper and a lower cylinder head, each head 'formed with an axial bore and secured in the upper and lower ends of said cylinder, respectively; a piston reciprocable in said cylinder; a plunger rod secured to said piston and extending through the bore formed injsaid upper cylinder head; an elongated conical extension secured to and extending from said piston toward the lower end of said cylinder; a fluid reservoir formed with a bore at its lower end and positioned ladjacent the upper end of said cylinder and in y uid communication with the upper end of said cylinder;

pipe means for permitting fluid communication between saidfluid reservoir and the lower portion of said cylinder, said :pipe means at one end thereof extending'throu'gh the bore of'said lower cylinder head into the lower end of said cylinder and sealed to said lower cylinder head and at its other end sealed into the bore formed in the lower end of said uid reservoir, the end of said'pipe means which extends into the lower end of said cylinder registering with the conical extension'of said piston whereby it is progressively constricted upon ymovement of said conical extension into said pipe means; and a quantity of shock absorbing fluid normally occupying a portion of said Huid reservoirland all space in lsaid shock absorber below said iluid reservoir.

References Cited in thev file of this 'patent i UNITED STATES PATENTS 1,752,072 'i Foster v v v Mar. ,25, 19.30 1,772,38f7-r v Dickerson Aug. 5, 1930 1,780,531 Messier Nov. 4, 19.30 2,038,032 A"f'FlyI1I1" Apr. 2 1, 1936i 2,069,791 jWallace'-- a Feb.9, 1937 FoREIGN PATENTS 121,688 Switzerland Oct. l, 17927 262,460 Switzerland Oct. l, 1949 ,126,831 Sweden Dec. 6,'1949 "720,302v Germany June 4, 1942r 

